Really interesting! Given that the baseball bat and goblin type enemies survived unchanged into the Sonic concept, it's fascinating to see more of the enemies that were conceived at a similar time period to those. Wonder if they were all still considered for inclusion until the "nightmare world" concept was dropped? Also interesting that the Green Hill style surroundings are recognisable even at this early pre-Sonic stage, complete with the iconic loop-de-loops! I'd always assumed those evolved as an idea based on the hedgehog character's rolling ability - apparently not...!